Commit 185b29c6 authored by Dan Carpenter's avatar Dan Carpenter Committed by Greg Kroah-Hartman
Browse files

test_firmware: fix end of loop test in upload_read_show() 



If a list_for_each_entry() loop exits without hitting a break statement
then the iterator points to invalid memory.  So in this code the
"tst->name" dereference is an out bounds read.  It's an offset from the
&test_upload_list pointer and it will likely work fine most of the time
but it's not correct.

One alternative is to fix this this by changing the test to:

	if (list_entry_is_head(tst, &test_upload_list, node)) {

But the simpler, trendy new way is just create a new variable and test
for NULL.

Fixes: a31ad463 ("test_firmware: Add test support for firmware upload")
Reviewed-by: default avatarRuss Weight <russell.h.weight@intel.com>
Acked-by: default avatarLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YnTGU3UJOIA09I7e@kili


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1f7ff11c

lib/test_firmware.c

+7 −4
Original line number Diff line number Diff line
@@ -1392,7 +1392,8 @@ static ssize_t upload_read_show(struct device *dev, 
				struct device_attribute *attr,

				char *buf)

{

	struct test_firmware_upload *tst;

	struct test_firmware_upload *tst = NULL;

	struct test_firmware_upload *tst_iter;

	int ret = -EINVAL;



	if (!test_fw_config->upload_name) {
@@ -1401,11 +1402,13 @@ static ssize_t upload_read_show(struct device *dev, 
	}



	mutex_lock(&test_fw_mutex);

	list_for_each_entry(tst, &test_upload_list, node)

		if (tst->name == test_fw_config->upload_name)

	list_for_each_entry(tst_iter, &test_upload_list, node)

		if (tst_iter->name == test_fw_config->upload_name) {

			tst = tst_iter;

			break;

		}



	if (tst->name != test_fw_config->upload_name) {

	if (!tst) {

		pr_err("Firmware name not found: %s\n",

		       test_fw_config->upload_name);

		goto out;